Effect of metal particle size and Nafion content on performance of MEA using Ir-V/C as anode catalyst

Abstract

Ir and Ir-V nanoparticles were synthesized in ethylene glycol using IrCl 3 and NH 4VO 3 as the Ir and V precursors, respectively. These nanoparticles were evaluated as anode catalysts in proton exchange membrane fuel cells (PEMFCs). A thermal treatment of the catalysts at 200 °C in a reducing atmosphere leads to very high electrocatalytic activity for the hydrogen oxidation reaction. The fuel cell performance reveals an optimal Nafion ionomer content of 25% in the catalyst layer used for the MEA fabrication. The electrocatalytic effects related to the change in the electrocatalyst structure are discussed based on the data obtained by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In addition, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques are used in-situ to assess the kinetics of hydrogen oxidation on the surface of these catalysts. A maximum power density of 1016.6 mW cm −2 was obtained at 0.598 V and 70 °C with an anode catalyst loading of 0.4 mg (Ir) cm −2. This performance is 50.7% higher than that for commercially available Pt/C catalysts under the same conditions. In addition, we also tested the anode catalyst with a low loading of 0.1 mg (Ir) cm −2, the maximum power density is 33.8% higher than that of the commercial Pt/C catalyst with a loading of 0.4 mg (Pt) cm −2.